Extended Abstract (272K)16C.4
Use of numerical weather prediction technology for simulations of historic tropical cyclones
Michael Dickinson, Accurate Environmental Forecasting Inc., Narragansett, RI; and G. D. Rowe, R. Richardson, I. Ginis, and L. Rothstein
The National Hurricane Center’s (NHC) Atlantic best track dataset is used by the scientific community as well as the private sector to determine hurricane climatologies from the Gulf of Mexico to New England. The best track dataset contains two pieces of information: (1) storm center positions and maximum wind speed (hereafter vitals) and (2) for landfalling hurricanes, a Saffir-Simpson category based on the maximum winds observed in each affected state. The best track dataset is currently undergoing a reanalysis by the Hurricane Research Division (HRD.
Our analysis is based on over-land wind swaths (‘footprints’) of all historic storms that affected land in the US since 1852. The storm footprints are produced by the AEF RealTrack™ system which guides a numerical weather prediction (NWP) hurricane model along the prescribed track. The hurricane model has a very high-resolution boundary layer combined with ultra high-resolution information about topography and land use. Using our storm footprint technology, we can determine the maximum wind each state experiences for the prescribed track and intensity record (the vitals). By comparing the resultant maximum state winds from our footprints to the state-based Saffir-Simpson categories in the best track dataset, we can validate the best-track dataset.
For a number of storms, the wind distribution implied by the vitals can not support the state-based Saffir-Simpson measurement in the affected state. For example, storm 7 of 1944 reported Category 3 winds in North Carolina, Virginia, New York, Connecticut, and Rhode Island. Yet, the maximum wind speeds in the vitals are below 90 kts from North Carolina to New England. This storm is crucial to the occurrence frequency assessment problem as it is the only category 3 storm report in Virginia. It is not clear which intensity measurement to believe. While this is the most egregious case, there are several other examples in the record in which the vitals can not support the state based wind.
Session 16C, tropical cyclone best track and climatology I
Friday, 7 May 2004, 8:00 AM-9:45 AM, Napoleon II Room
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